I purchased an Excel program from Yeldell Scientific. After opening the file Microsoft alerted "Malicious File" I E-mailed Jason Yeldell the "CEO". He said it was not a Scam.I continued the file. It was an Excel document for taking stock and inventory for my small business. I began taking stock. I then discovered erorrs in the programing. A diagnostic from Microsoft Defender said the file was "A severe Trojan Virus." Recommending to uninstall the program, and quarintine my computer. I E-mailed Jason Yeldell asking for a refund. He ignored my E-mail. I since have attempted to call, Yeldell Scientific, but still am ignored. I made a comment on Yeldell Scientific’s Facebook page, and was immediately blocked. I have opened a paypal claim against Yeldell Scientific, but still refuses to responed.This is SCAM. Do not trust Yeldell Scientific.